Hello all. I recently fitted a Vance and Hines 4into1 (round can not oval) , DynoJet kit, and K&n filter to my '94 CBR1000F. After much fiddling with jet sizes and needle heights and fitting the original springs back on top of the diaphragms (the DynoJet ones let them lift the needles too fast and left a lag when I went full bore through the gears), I have it running well. however I'm not happy with the sound. It's a bit tinny and gurgles a bit when I'm trying to slip through town on low revs. I knew it would be quite loud and with all the kangaroos I meet on the 100km round trip to work and home loud is a good thing. I am thinking of putting in a smaller diameter baffle tube (about 10mm smaller) to allow for a bit more packing and possibly a slightly smaller sound tube in the end. I don't think I'll loose too much breathing and maybe a bit of back pressure is a good thing.

I would appreciate any thoughts you guys have as many heads are better than one.

Thanks, Dave.

 

I tried re-packing my pipe and it made a bit of difference but not much. Unfortunately to get that deep sound you need a thick heavy muffler. You can try different packing. At a guess I'd say the V&H uses fibreglass. I got mine done with a ceramic type cloth which is better, but if you pack it too tight it won't absorb sounds either.

BTW, just out of curiosity, what settings are your Pilots, main jets & needle heights at? Also how much difference did going back to the original carb springs make?

 

Thanks for responding. I have already re-packed my muffler a couple of times, but I will take on board what you wrote about packing too tight.
My pilots are about two turns out, main jets are 120, and needles are on the second from the top (second leanest). I tried them on the leanest and third groove from the top, but in between seems right.
With the DynoJet springs in the motor would rev instantly when on the stand, but when I went from full throttle @10,000rpm in first and then to the same in second etc. there was a split second where I had nothing. I think the needles were lifting too fast for any fuel to be there. With the standard springs there is no delay whatsoever, just instant power.
The V&H sounds great when you are really up it, but I still want to adjust the sound low down. I have ordered a length of 45mm baffle tube, down from about 55mm so I'll get a bit more packing in and I will try that before putting in a slightly smaller sound tube. Idon't think I will lose performance but if I do I'll fit a different muffler to my V&H headers (when finances allow!) Any suggestions?

Watch out for roos!! Dave.

 

Hey Dave, where abouts in Oz is Dalveen?

 

I might have to reef the carby's out on the weekend. I had my Pilot at 3 turns out and mains at 125. Just like you I had the big hole just off idle.

If the slides are coming up to fast I'd love to know if I could drill them as some people do. But costly if you fsck it up!

The only way to see about the exhaust is to try. See if you can get a smaller baffle from a wrecker or a car exhaust shop.

 

Is that in-between Warwick and Stanthorpe

 

"when I went from full throttle @10,000rpm in first and then to the same in second etc. there was a split second where I had nothing"
That was my experience right after re-jetting, turned out it was because I didnt install the airbox side correctly onto the carbs. Make sure their arent any air or vacuum leaks.

 

Yes, Dalveen is in between Warwick and Stanthorpe in South East Queensland.
I got 124 and 120 jets with my DynoJet kit. With the 124s in if I went from about five grand in top to full throttle and just held it wide open it just felt a bit flat, like it had more to give but just couldn't. It's hard to explain, but you know when it's not quite right. the 120s fixed that problem, but I still had the totally dead split second going from a gear change at full revs to full throttle in the next gear. Fitting the original springs fixed this perfectly.
If you don't have your original springs and can't get hold of any try your local auto spares shop and look at their collection of compression springs for ones that are longer and slightly heavier than yours. I lost my choke spring somewhere during the many times the carbs were off and went into the shop without much hope of finding anything suitable, only to be given too much choice! A rare thing.
I would try this or anything else before doing anything involving a drill. Like you say if you fxck it you are in for big money.
I'm sure I don't have any intake leaks, but thanks for responding.
I picked up a smaller baffle tube today and will get the local exhaust guy to flare me up some bits of pipe to make it fit, and I'm getting the carbs balanced next Monday.
Bye for now, Dave.

 

Were you running a K&N FIler?

When you tried the needle positions either side of current setting which was worse going leaner or richer?

Thanks
Rob

 

Yes I am using a K&N filter. One groove richer was MUCH worse than one leaner. I only rode down to my front gate and could tell it was wrong. On the leaner setting it ran ok but I believe you are better to be on the richer side than the leaner.
After I get my pilot screws adjusted and carbs balanced I'll let you know how many turns out the screws are but bear in mind I'm at about 850m above sea level.
Oh well, I'll go and drink another Cooper's and watch Futurama.
Cheers, Dave.